Operating Basics: User Interface
OTS9100 User Manual 2-29
Background Channels
The Background Channels section controls the settings for signal structure and test pattern of the
non-active channels.

Signal Structure

Signal structure allows the user to choose the mapping structure for the background channels of
the transmitted signal. The mapping structures provided for background channels are listed in
the table below.
SONET SDH
1 x STS-192c 1 x VC4-64c
4 x STS-48c 4 x VC4-16c
16 x STS-12c 12 x VC4-4c
64 x STS-3c 64 x VC4
192 x STS-1 192 x VC3

Test Pattern

Test Pattern allows the user to select one of four available patterns to fill the background of the
internally generated 9.95238 Gb/s signal. The default pattern fill is inverted PN23. The patterns
available are:
Inverted PN23 (ITU O.151)
All Zeros
All Ones
Fixed Data (8-bit)
When Fixed Data is selected a button marked Edit Fixed Data is displayed. To change the Fixed
Data to a different value, click the Edit Fixed Data button and type the new value into the text
box beside the button. In the Test Pattern selection box, observe that the value after Fixed Data
changes to match the newly entered value.
SPE/VC3 Stuff Column Control
The stuff column control allows column 30 and column 59 of the SPE (VC3) to be stuffed with
either all zeros or with the selected payload pattern. This option is only available if the pattern
Background Signal Structure is STS-1 or VC3.